The proposed law tabled by Mr McGrath aims to hand more power to the Central Bank to reduce interest rates.

The Fianna Fáil finance spokesman insisted the bill was “constitutional” as a vote on it is set to pass tomorrow after Sinn Féin announced their plan to support it also.

“I find it bizarre that Minister Noonan would refer to constitutional issues because this very bill was debated in the Dáil last July and the Government responded to the bill then and raised no constitutional concerns,” Mr McGrath said.

He played down Mr Noonan's comments saying he was referring to an investment bank's opinion on the Constitution and not the Attorney General, who advises the Government.

Mr McGrath also said that Central Bank was not “infallible” after its Governor General Philip Lane said the bill was “simplistic.”

“I would also make the point, I heard time and time again at the Banking Inquiry, how the Central Bank was not robustly challenged and how the banks themselves were not robustly challenged during the Celtic Tiger years."